Currently, there are four widely used battery cell structures: button/coin cell, cylindrical cell, prismatic cell, and pouch cell. For the relatively small button/coin cell, usually one layer of anode is separated from the cathode by a thin film separator. The three layers are sealed in a metal case. The other three structures follow the wound design; i.e., electrodes and separator are cut into sheets, layered, and wound into spiral rolls or flatten rolls, which are sealed by metal or plastic containers. All these cells can be used in electric vehicles (EV), and a few special cell structures have sometimes been employed. For example: the inner structure of wound electrodes and separators can be redesigned by applying various stack and fold patterns; low aspect ratio tube cell structures have been proposed for better thermal management; battery cases have been redesigned and case materials selected to lower internal resistance, improve thermal management, simplify cell assembly, or reduce cell mass density. Special deformable and displaceable battery packs have been designed to absorb energy in a vehicle collision. Battery cells and battery structures can be designed to improve the performance of batteries as an electrical component. For example, by increasing their power capacity and density, extending battery life, improving the usage of space, and improving battery safety, etc.
Casualties can result when conventional battery cells are crushed at a very high deceleration in a crash event. Proposals for load carrying battery cells have generally centered on strengthening of battery materials.